1. Field of the Invention
The present invention relates to a photographing apparatus, such as a digital camera, and, in particular, to a photographing apparatus and method in which light is irradiated onto a subject.
2. Description of the Related Art
Recently, various methods for measuring a three-dimensional shape of a predetermined object using a photographing apparatus, such as a digital camera, have been proposed. One of the methods is a stereo matching method in which a predetermined object is imaged from different directions using a plurality or a single photographing apparatus to obtain a plurality of sets of image data, then a commonly imaged point in each set of image data (reference point) is identified, and distances to the reference point are measured according to the triangulation principle to estimate the three-dimensional shape of the predetermined object. The methods for identifying the reference point include a method in which a characteristic point of the predetermined object within the image data is visually specified by a person, a method in which patterned light, such as spot light or slit light, is irradiated on the predetermined object when photographing and a spot produced by the spot beam or a straight line produced by the slit beam is used as the reference point, or the like.
Another method for measuring a three-dimensional shape is also known as described, for example, in Japanese Unexamined Patent Publication No. 2006-023131, in which specifically patterned light is irradiated onto a subject when photographing and a predetermined object is photographed from the same direction as the optical axis of the patterned light and from a direction different from the optical axis to obtain image data of the predetermined object, and the shape of the predetermined object is estimated by analyzing the variation in the shape within the obtained image data, such as the distortion of the patterned light or the like.
In the mean time, digital cameras using CMOS or CCD image sensors are provided as generally available photographing devices. In the digital cameras using such type of image sensors, it is common to perform focus control of the taking lens while evaluating the formation of a subject image on the image sensor. In the evaluation of the image formation, an image signal obtained from each pixel of the image sensor is used, and the focus control of the taking lens is performed, for example, such that the evaluation value which is the integrated value of difference in the signal level between adjacent pixels becomes maximum. Another method is also known as described, for example, in Japanese Unexamined Patent Publication No. 2004-317699, in which a region corresponding to the face portion of a person is specified within a subject image, and the focus control is performed using the face portion of the subject.
When focus control of the taking lens is performed based the image signals from the image sensor in the manner as described above, it is often the case that the focus control is not performed properly under photographing conditions in which the overall subject brightness is reduced, such as during the nighttime or in a dark place, since the contrast of the subject itself becomes low. Under such circumstances, a method is proposed as described, for example, in Japanese Unexamined Patent Publication No. 2003-098579, in which an auxiliary light projector is provided in a camera body, and auxiliary light is irradiated onto a subject when focus control of the taking lens is performed. The irradiation of the auxiliary light onto the subject increases the subject brightness, and thereby the focus control of the taking lens may be performed properly.
In the method for photographing a predetermined object by irradiating patterned light as described above, however, the beam may sometimes be irradiated also on an area of the subject which does not want the beam to be irradiated. For example, when measuring the three-dimensional shape of a human face, the beam forming the reference point may be irradiated onto the eyes of the person, which poses a problem that the person is dazzled.
Further, in the case of a digital camera in which the focus control is performed using the face portion of a person or the like, the auxiliary light is naturally irradiated on the face portion, and the auxiliary light may enter into the eyes of the person so that it has a disadvantage that the person is caused to feel dazzled.
The present invention has been developed in view of the circumstances described above, and it is an object of the present invention to provide a photographing apparatus and method capable of not causing a subject to feel dazzled by the light irradiated when photographing.